Flower Description:

Lobelia siphilitica produces striking, tubular flowers in shades of vivid blue to lavender, often with a subtle two-lipped structure. The blooms appear densely packed along upright flower spikes, each reaching up to 3 feet (90 cm) tall. Flowering occurs from late summer into early fall, providing a burst of color when many other plants are past their prime. The nectar-rich flowers are highly attractive to hummingbirds, butterflies, and bees, making them a favorite in pollinator gardens.

Fruit Description:

After flowering, Lobelia siphilitica forms small, inconspicuous seed capsules. These capsules contain numerous tiny, brown seeds that can readily self-sow in moist conditions. While the fruits are not ornamental, they contribute to the plant’s ability to naturalize in suitable environments, making it a great option for meadow or wildflower settings.

Foliage Description:

The foliage consists of lance-shaped, medium-green leaves with a slightly serrated edge. The leaves grow alternately along the stem, measuring 3–6 inches (7–15 cm) long. They form a dense, basal rosette from which the flowering stalks emerge. The foliage provides a lush, verdant backdrop for the vibrant flower spikes and remains attractive throughout the growing season, adding texture and fullness to garden beds and borders.

Lobelia siphilitica, commonly known as Great Blue Lobelia or Blue Cardinal Flower, is a herbaceous perennial native to eastern and central North America. It is cherished for its vibrant blue flowers and its ability to attract pollinators such as hummingbirds and butterflies.

Planting and Location:

• Sunlight: Prefers full sun to partial shade. In warmer climates, partial shade during the hottest part of the day can help prevent stress.
• Soil: Thrives in moist, rich, well-drained soils. It tolerates a range of soil types, including loamy and clay soils, as long as adequate moisture is maintained.
• Spacing: Space plants about 12 inches apart to allow for proper air circulation and growth.

Watering:

• Moisture Needs: Requires consistently moist soil. Regular watering is essential, especially during dry periods, to keep the top 6 inches of soil moist. Mulching can help retain soil moisture.

Fertilization:

• Generally does not require additional fertilization if planted in rich soil. In poorer soils, incorporating compost or a balanced, slow-release fertilizer in early spring can promote healthy growth.

Pruning:

• Deadheading: Removing spent flowers can encourage continued blooming and prevent unwanted self-seeding. However, allowing some seed heads to mature can facilitate natural reseeding if desired.
• Cutting Back: After the first frost, stems can be cut back to the ground to tidy the garden and prepare for new growth in spring.

Pests and Diseases:

• Generally resistant to deer and rabbits. However, slugs and snails may feed on the foliage. Maintaining good garden hygiene and using organic slug control methods can help manage these pests.

Additional Considerations:

• Wildlife Attraction: The nectar-rich flowers attract hummingbirds, butterflies, and bees, making it a valuable addition to pollinator gardens.
• Landscape Use: Ideal for rain gardens, woodland gardens, and along streams or ponds due to its moisture-loving nature. It adds late-season color, typically blooming from late summer into fall.